1. Technical Field
The present disclosure relates to retractable safety needles. More particularly, the present disclosure relates to retractable safety needles incorporating a spring biased retraction mechanism that provides a constant force to an associated needle assembly during retraction of the needle assembly.
2. Background of Related Art
Hypodermic needles are used for venous access in a variety of medical procedures including fluid sampling, percutaneous medication injection, and other fluid delivery or withdrawal procedures. Some of the health risks associated with hazardous needle exposure includes HIV, hepatitis, and other blood-borne pathogens. Medical professionals are in danger of contracting such blood-borne pathogens from infected patients by inadvertent needle sticks from needles contaminated during medical procedures.
Various protective devices including sheaths, have been used to shield sharp tips of needles in order to alleviate danger of needlestick injury to a user. Additionally, many needle devices include the provision of an automatic retraction system to shield the needle within a housing associated with the needle assembly after use.
Commercially available needle devices that include the provision of an automatic retraction system typically rely on the use of compression springs to provide the needed retraction forces. The compression springs utilized by these systems provide high forces at full compression of the spring and little or no force at full extension of the spring. As a result, extreme force changes are present when the needle is moved from an extended position to a retracted position, which, in turn may result in accidental needlestick injuries, blood splattering, or other undesirable outcomes. In addition, compression springs are bulky and, thus, may require an increase in the cross-section of the needle device to accommodate the spring.
Therefore, it would be desirable to provide a safety needle device which includes a spring mechanism that provides a constant force throughout retraction and/or extension of the needle. It would be further desirable to provide a spring mechanism which is simple, low-cost, and can be easily incorporated into existing safety needle devices.